An X-ray detector will be described by way of example. The X-ray detector includes an X-ray conversion layer of an X-ray sensitive type. The detector detects X-rays by converting X-rays into electric charge information with the X-ray conversion layer upon incidence of the X-rays and reading out the electric charge information converted. Since the electric charges converted from the X-rays with the X-ray conversion layer are extremely small, the electric charges need to be amplified. The extremely small electric charges may occur not only from the X-rays but also changes in static electricity. Thus, where an electric potential change occurs from static electricity with respect to signal lines such as data lines at a previous stage of an amplifier, the change in the static electricity is identified as a signal by mistake to be amplified altogether. This results in occurrence of noise. There is a technique in which dummy lines to reduce influences of such static electricity are arranged in the thin film transistor (TFT) itself, thereby suppressing noise from the static electricity (see, for example, patent document 1.)
Here, according to a direct conversion type X-ray detector configured to convert incident radiation directly into charge information with an X-ray conversion layer, electric charges are generated with the X-ray conversion layer upon incidence of X-rays. In that case, it is necessary to apply a high bias voltage (for example, around several hundreds V to several tens kV) to the X-ray conversion layer. Electric discharge needs to be prevented for application of a high voltage. Thus, measures will be taken such as covering of the conversion layer with an insulator generally called a “molding structure.” A frame is provided around the perimeter of the X-ray conversion layer or voltage application electrode, and an insulator such as a glass is placed on the frame. Subsequently, an insulating resin is poured into a space between the X-ray conversion layer or voltage application electrode and the glass for sealing. Such a configuration is general and leads to covering and protecting of the X-ray conversion layer or voltage application electrode with the insulating resin.
No electric discharge will occur in an applying surface of the voltage application electrode covered with the insulator such as the molding structure. On the other hand, static electricity will occur in an incidence surface (i.e., an opposed surface of the applying surface) of the molding structure. Consequently, the amplifier amplifies the change in the static electricity altogether, as mentioned above, leading to occurrence of noise. Such molding structure includes a technique to remove the static electricity using a conductive member grounded instead of the glass, thereby suppressing occurrence of the noise from the static electricity (see, for example, patent document 2.)
There is another technique in which the grounded conductive member is arranged between a photo-timer and X-ray detector for blocking of radiation noise from the photo-timer and dissipating the radiation noise through the ground (see, for example, patent document 3.)
[Patent Document 1]
JP2003-46075A1 (Page 2 to 11, FIG. 1)
[Patent Document 2]
JP2004-268271A1 (Page 1 to 9, FIG. 1)
[Patent Document 3]
JP2005-241334A1 (Page 1 to 6, FIGS. 2, 3)